IRS NOTICE REFERENCE
Understanding your Letter 12C
We need more information to process your individual income tax return. Information needed could be: Missing or corrected forms or schedules to support your entries on Form 1040, U.S. Individual Tax Form or Form 1040-SR, …
General information only. Not legal or tax advice.
Notice details
- Notice code
- Letter 12C
- Category
- Identity verification
- Severity tier
- Tier 2 — Action or response expected. The IRS has taken or proposed an action and expects a response or payment.
- Governing law
- §6109; §7701(a)(16) (Internal Revenue Code sections)
- Statutory response window
- 20-day window — always confirm the exact deadline against the date printed on your notice.
- Source
- IRS.gov — Understanding Your IRS Notice
What this notice is
We need more information to process your individual income tax return. Information needed could be: Missing or corrected forms or schedules to support your entries on Form 1040, U.S. Individual Tax Form or Form 1040-SR, U.S. Income Tax Return for Seniors . Verification of income, withholding and credit amounts. Verification of taxpayer identification numbers or Social Security numbers. We’ll send any refund due about 6-8 weeks after we receive your response.
Source: IRS.gov. Reproduced for reference. General information — not legal or tax advice.
What the IRS says to do
Read your letter carefully. Send the information we requested within 20 days. Respond to the letter, even if you disagree, providing a clear explanation of what you disagree with. Do not file a Form 1040-X, Amended U.S. Individual Income Tax Return.
This is the IRS’s own guidance reproduced from the IRS notice page. It describes the IRS’s process — it is not legal or tax advice from TaxRiskOS.
Official IRS reference
Read the official notice page on IRS.gov: https://www.irs.gov/individuals/understanding-your-letter-12c
Related tools
TaxRiskOS is workflow software for practitioners — it captures the notice, computes the deadline, surfaces the escalation tier, and builds a document checklist. It documents process; it does not give advice or draft responses.
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